JP2007124858A - Motor control device and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor control device that has less waveform distortion maintaining the resolution of PWM signals and its control method. <P>SOLUTION: The motor control device (1) comprises a position control unit (11) that generates a speed command from positional deviation of a positional command and a position, a speed control unit (12) that generates a torque command from the speed deviation of a speed command and speed, a current command generation unit that generates a current command from the torque command, a current control unit (13) that generates a voltage command from current deviation of the current command and a current, a carrier generation unit (15) that generates a carrier signal of the PWM signals, and an E-O conversion unit (17) that converts the electric signals of the voltage command and the carrier signal into optical signals. A drive unit (2) comprises an O-E conversion unit 21 that converts the optical signals into the electrical ones, a voltage command regeneration unit (22) that reproduce a voltage command from the electric signals, a carrier signal regeneration unit (24) that reproduces the carrier signal from the electric signals, and a PWM signal generation unit (23) that generates PWM signals from the regenerated voltage command and the regenerated carrier signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric motor control device particularly suitable for controlling a high-voltage electric motor and a control method therefor.

  There exists patent document 1 in the motor control apparatus of a prior art. The prior art will be described with reference to the drawings. FIG. 2 is a block diagram showing a conventional motor control device applied to an electric vehicle. In FIG. 2, 101 is a control device, 102 is a gate drive circuit, 103 is a main circuit, 104 is a filter capacitor, 105 is a cab, 106 is a motor, 107 is a DC voltage sensor, and 108 is a sensor unit.

  Next, the operation will be described. The inverter device is connected to a main circuit 103 composed of a switching element (IGBT element) that converts a DC voltage Vd into three-phase motor currents i u, i v, i w, and the like, and is connected to the DC side of the main circuit 103. The filter capacitor 104 for supplying DC power to the main circuit 103 and smoothing it, and generating a modulation rate based on the operation command from the cab 105, the detected motor current, and the filter capacitor voltage are converted into PWM pulses. The control device 101 converts the information a into the gate drive 102 and outputs it to the gate drive 102, and the gate drive 102 converts the PWM information a into the gate signal b of the switching element in the main circuit 103. The cab 105 outputs operation commands such as power running, regeneration command, notch signal, and brake command. This operation command is transmitted to the control device 101 via the serial transmission cable 109C. An AC motor 106 that drives the electric vehicle is connected to the AC side of the main circuit 103. Although not clearly shown in FIG. 2, the main circuit 103 includes two poles of each of the three phases of U V W × P · N side = 6 IGBT elements. Six gate signals b are sent to the circuit 103, and similarly, PWM pulse information a sent from the control device 1 to the gate drive 102 is also sent via six signal lines. A DC voltage sensor (PT) 7 for detecting the terminal voltage Vd of the filter capacitor 104 is provided on the DC side of the main circuit 103, and a motor current for detecting instantaneous values of the motor currents iu, iv, iw is provided on the AC side. A sensor unit 108 is provided. Each sensor 107 and 108 is provided with an input and an output as connection terminals for serial signal transmission. Thereby, the output connection terminal of the DC voltage sensor (PT) 7 and the input connection terminal of the motor current sensor unit 108 are connected by the serial transmission cable 109A, and the output connection terminal of the sensor unit 8 and the input of the control device 101 are connected. The connection terminals are connected by a serial transmission cable 109B. As described above, the sensors 107 and 108 and the control device 101 are connected in series via the serial transmission cables 9A to 9B.

3 is a detailed configuration diagram of the control device 101 in FIG. 2, in which 203 is a pulse output unit, 204 is an E / O conversion unit, 205a and 205b are storage devices, 207 is an operation command generation unit, and 208 is a current command generation. 209, a current detector, 210 an instantaneous current controller, 211 a speed estimator, 212 a phase estimator, and 213 a modulation factor calculator. A current command is generated by an operation command, a current signal is reproduced from data transmitted as serial data, instantaneous current control is performed, and a PWM gate drive signal generated by the pulse output device 203 is subjected to E / O conversion. It is transmitted to the gate drive unit 102 of the main circuit.
International Publication No. 00/19590 pamphlet

However, the conventional motor control device has a problem in that the resolution of the PWM pulse is restricted by the communication cycle, so that the control accuracy is not improved and the waveform is distorted.
The present invention has been made in view of such problems, and an object of the present invention is to provide an electric motor control device with less waveform distortion that retains the resolution of the PWM signal and a control method therefor.

According to the first aspect of the present invention, there is provided an electric motor control device including a control unit, a drive unit, a main circuit, and an optical cable connecting the control unit and the drive unit. A position control unit that generates a speed command from the deviation, a speed control unit that generates a torque command from the speed command and the speed deviation of the speed, a current command generation unit that generates a current command from the torque command, a current command and a current of the current A current control unit that generates a voltage command from the deviation; a carrier generation unit that generates a carrier signal of the PWM signal; and an E / O conversion unit that converts the voltage command and the carrier signal from an electrical signal to an optical signal. An O / E converter that converts an optical signal into an electrical signal, a voltage command regeneration unit that regenerates a voltage command from the electrical signal, a carrier signal regeneration unit that regenerates a carrier signal from the electrical signal, and a regeneration voltage command and regeneration From Yaria signal is obtained so as to include a PWM generator for generating a PWM signal.
According to a second aspect of the present invention, in the electric control apparatus according to the first aspect, the carrier signal includes a carrier period and a carrier phase, and the carrier signal reproduced between the multiple cells has a phase difference.
According to a third aspect of the present invention, in the electric motor control apparatus according to the first aspect, the voltage command is composed of one or more, and the voltage command is reproduced by interpolation.
According to a fourth aspect of the present invention, there is provided the motor control device according to the first aspect, wherein the main circuit current is AD-converted to generate a current signal, and the second signal E is converted to an optical signal. A / O conversion unit, a second O / E conversion unit that converts an optical signal into an electrical signal, and a current signal regeneration unit that regenerates a current signal from the optical signal.
According to a fifth aspect of the present invention, there is provided a control method for an electric motor control device including a control unit, a drive unit, a main circuit, and an optical cable connecting the control unit and the drive unit. A step of generating a speed command from the position deviation of the position, a step of generating a torque command from the speed command and the speed deviation of the speed, a step of generating a current command from the torque command, and a voltage command from the current deviation of the current command and the current Generating a PWM signal carrier, converting the voltage command and the carrier signal from an electrical signal to an optical signal, and the drive unit converting the optical signal to an electrical signal; Regenerating the voltage command from the electrical signal, regenerating the carrier signal from the electrical signal, and generating a PWM signal from the regenerated voltage command and the regenerated carrier signal It is obtained so as to include the steps.

  According to the present invention, it is possible to provide an electric motor control device that maintains the resolution of a PWM signal and has little waveform distortion, and a control method therefor.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention. In FIG. 1, 1 is a control part, 2 is a drive part, 3 is an electric motor, 4 is a position detector. Further, 11 is a position control unit, 12 is a speed control unit, 13 is a current control unit, 14 is a voltage command generation unit, 15 is a carrier signal generation unit, 16 is a current signal regeneration unit, 17 is an E / O conversion unit, 18 Is a second O / E converter. Furthermore, 21 is an O / E conversion unit, 22 is a voltage command reproduction unit, 23 is a PWM signal generation unit, 24 is a carrier signal reproduction unit, 25 is an AD conversion unit, and 26 is a second E / O conversion unit.

  Next, the operation will be described. The position control unit 11 generates a speed command by multiplying a position deviation, which is a difference between the position command and the position, by a proportional gain Kp. The speed controller 12 generates a first torque command by multiplying the speed deviation, which is the difference between the speed command and the speed, by a proportional gain Kv. Further, the first torque command is integrated in the control cycle and divided by the integration time Tvi to generate a second torque command. Further, the first torque command and the second torque command are added to generate a torque command. Further, a current command is generated from the torque command. The current controller 13 multiplies the current deviation, which is the difference between the current command and the current, by the proportional gain Kc to generate a first voltage command. Further, the first voltage command is integrated for the control time and divided by the integration time constant Tci to generate a second voltage command. Further, the voltage command generation unit 14 adds the first voltage command and the second voltage command to generate a voltage command. The carrier signal generation unit 15 generates a carrier signal necessary for PWM signal generation. An E / O conversion (electric / optical conversion) unit 17 converts a voltage command and a carrier signal from an electric signal to an optical signal, and further, via an optical cable 6, an O / E (optical / electrical conversion) unit 21 of the drive unit 2. Transmit to. The O / E converter 21 converts an optical signal into an electric signal. The voltage command regeneration unit 22 regenerates the voltage command from the electrical signal and generates a regeneration voltage command. The carrier signal reproducing unit generates a reproduced carrier signal from the electric signal. The PWM generation unit compares the reproduction voltage command with the reproduction carrier signal, generates a PWM signal, and transmits the PWM signal to a gate drive unit (not shown) of the main circuit. The main circuit 3 is driven by a gate drive unit and drives an electric motor. Further, the current of the main circuit 3 is converted into a serial signal by the AD conversion unit 25 and is transmitted from the drive unit 2 to the control unit 1 via the second E / O conversion unit and the second O / E conversion. The signal reproduction unit 16 generates a reproduction current signal and is used for current control.

  Next, communication data transmitted from the control unit 1 to the drive unit 2 will be described. Communication data is transmitted in two modes: a carrier transmission mode and a voltage command transmission mode. FIG. 4 shows carrier signal data, which includes a start bit, a carrier transmission mode section, a synchronization signal SYN, carrier synchronization data, carrier phase, operation cycle data, CRC check, and stop bit. FIG. 5 shows voltage command data, which includes a start bit, a voltage command transmission mode, a synchronization signal SYNC, voltage command data, a CRC check, and a stop bit. The carrier transmission mode is executed only once at the time of initial setting of the electric motor driving device, and the carrier signal is composed of carrier cycle data, carrier phase data, and calculation cycle data. In the voltage command transmission mode, data is transmitted every communication cycle, and the data includes one or more voltage command data and a synchronization signal for carrier synchronization.

  Next, the carrier reproducing unit will be described. FIG. 6 is a block diagram showing the configuration of the carrier reproduction unit, in which 51 is a carrier cycle register, 52 is a carrier counter, 53 is a carrier phase register, 54 is a comparison unit, and 55 is a PWM carrier counter. Carrier cycle data is set in the carrier cycle register 51, and carrier phase data is set in the carrier phase register 53. The carrier counter 52 is an up counter that is cleared when the counter value matches the carrier cycle register value or when a synchronization signal is input, and the output value of the carrier counter 52 is synchronized with the synchronization signal as shown in FIG. It becomes a triangular wave of the carrier period. The comparator 54 compares the value of the carrier counter 52 with the value of the carrier phase register 53, and outputs a PWM carrier counter clear signal when they match. The PWM carrier counter 55 is an up counter at the time of clearing, and is an up / down counter that becomes a down counter at 1/2 of the carrier cycle. As shown in FIG. To do. FIG. 7 shows operation waveforms of the carrier reproducing unit. The carrier signal is reproduced by the carrier period data and carrier phase data transmitted in the carrier transmission mode and the synchronization signal transmitted in the voltage command transmission mode.

  Next, the voltage command regeneration unit will be described. FIG. 8 is a block diagram of the voltage command reproducing unit, 61 is a calculation cycle register, 62 is a voltage command register, 63 is a previous voltage command register, 64 is a difference register, 65 is a pulse distribution unit, and 66 is a voltage command output counter. . When the voltage command reception is completed, the previous value voltage command register 63 stores the value of the voltage command register 62, and the voltage command register 62 stores the received new voltage command data. Further, the difference between the value of the voltage command register 62 and the value of the previous value voltage command register 63 is stored in the difference register 64. The pulse distribution circuit 65 generates the number of pulses of the value of the difference register 64 at equal intervals at the time set in the calculation cycle register 61. An up pulse is generated when the difference is positive, and a down pulse is generated when the difference is negative. The voltage command output counter 66 is an up / down counter in which the value of the previous value voltage command register 62 is preset when the command is updated, and is counted up by an up pulse and counted down by a down pulse. The voltage command reproduction unit generates a linear interpolation value that becomes the value of the voltage command register 63 at the previous time when the command is updated and becomes the value of the voltage command register 62 immediately before the command is updated. The PWM signal generator compares the regenerated carrier signal as shown in FIG. 9 with the regenerated voltage command to generate a PWM signal.

Next, a control method will be described. FIG. 10 is a flowchart for transmitting a carrier signal, which is transmitted only once at the time of initial setting. In FIG. 10, a carrier signal is generated in step SA1, and an electric signal of the carrier is converted into an optical signal in step SA2. In step SA3, the optical signal is transmitted to the drive unit, converted into an electric signal in step SA4, and the carrier signal is reproduced in step SA5. FIG. 11 is a flowchart showing transmission of a voltage command performed for each control cycle. In FIG. 11, in step SB1, a speed command is generated by obtaining a position deviation from the position command and the position signal. Next, in step SB2, a torque command is generated by obtaining a speed deviation from the speed command and the speed. Next, in step SB3, a current command is generated from the torque command. Next, in step SB4, a voltage command is generated by obtaining a current deviation from the current command and the current. Next, in step SB5, the voltage command electric signal is converted into an optical signal. Next, in step SB6, an optical signal is transmitted to the drive unit. In step SB7, the optical signal is converted into an electric signal. Next, in step SB8, the voltage command is regenerated from the electrical signal. Next, in step SB9, a PWM signal is generated from the voltage command and the carrier signal reproduced earlier to drive the main circuit. FIG. 12 is a flowchart showing the regeneration of the current signal performed at each control cycle. In FIG. 12, in step SC1, the main circuit current is converted into a serial signal. Next, in step SC2, the electrical signal is converted into an optical signal. Next, in step SC3, the optical signal is transmitted to the control unit 1. Step SC4 regenerates a current signal from the optical signal and uses it as a current in FIG. 11 for control.
The resolution of the PWM signal generated in the embodiment depends on the operation clock frequency of the voltage reproduction circuit and the carrier reproduction circuit, and does not depend on the communication cycle.

  Since the present invention can provide an electric motor control device that maintains the resolution of a PWM signal and has little waveform distortion, and its control method, it can be applied to general industrial machines and machine tools. Further, since the control unit and the drive unit are insulated by light, application to high voltage motor control can be expected.

The block diagram which shows the structure of this invention. The block diagram which shows the structure of a prior art example. Block diagram showing details of configuration of conventional example Carrier signal communication data. Communication data for voltage command. The block diagram which shows the structure of a carrier reproducing part. Reproduced carrier signal waveform. The block diagram which shows the structure of a voltage instruction | command reproduction | regeneration part. The waveform of the PWM signal generator. Flowchart of carrier signal transmission of the present invention Flow chart of voltage command transmission of the present invention Flowchart for transmitting a current signal of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control part 2 Drive part 3 Main circuit 4 Electric motor 5 Position detector 6, 7 Optical cable 11 Position control part 12 Speed control part 13 Current control part 14 Voltage command generation part 15 Carrier generation part 16 Current signal reproduction | regeneration part 17 E / O conversion Unit 18 second O / E conversion unit 21 O / E conversion unit 22 voltage command reproduction unit 23 PWM signal generation unit 24 carrier signal reproduction unit 25 AD conversion unit 26 second E / O conversion unit 51 carrier cycle register 52 carrier Counter 53 Carrier phase register 54 Comparison unit 55 PWM carrier counter 61 Calculation cycle register 62 Voltage command register 63 Previous voltage command register 64 Difference register 65 Pulse distribution unit 66 Voltage command output counter

Claims (5)

In an electric motor control device including a control unit, a drive unit, a main circuit, and an optical cable connecting the control unit and the drive unit,
The control unit generates a speed command from a position command and a position deviation of the position;
A speed control unit that generates a torque command from the speed command and a speed deviation of the speed;
A current command generator for generating a current command from the torque command;
A current control unit that generates a voltage command from the current command and a current deviation of the current;
A carrier generator for generating a carrier signal of the PWM signal;
An E / O converter that converts the voltage command and the carrier signal from an electrical signal to an optical signal;
The drive unit is
An O / E converter that converts the optical signal into an electrical signal;
A voltage command regenerator that regenerates a voltage command from the electrical signal;
A machine carrier signal reproducing unit for reproducing a carrier signal from the electrical signal;
An electric motor control device comprising: a PWM generation unit that generates a PWM signal from the reproduction voltage command and the reproduction carrier signal.   The motor control device according to claim 1, wherein the carrier signal includes a carrier cycle and a carrier phase, and a carrier signal reproduced between multiple cells has a phase difference.   2. The motor control device according to claim 1, wherein the voltage command is composed of one or more, and the voltage command is reproduced by interpolation. An AD converter that AD converts the current of the main circuit to generate a current signal;
A second E / O converter that converts the current signal into an optical signal;
A second O / E converter that converts the optical signal into an electrical signal;
A current signal reproducing unit for reproducing a current signal from the optical signal;
The electric motor control device according to claim 1, comprising: In a control method for an electric motor control device including a control unit, a drive unit, a main circuit, and an optical cable connecting the control unit and the drive unit,
The controller is
During initial setup,
Generating a carrier of the PWM signal;
Converting the carrier signal from an electrical signal to an optical signal;
Transmitting the optical signal to the drive unit;
For each control cycle,
Generating a speed command from the position command and the position deviation of the position;
Generating a torque command from the speed command and a speed deviation of the speed;
Generating a current command from the torque command;
Generating a voltage command from the current command and a current deviation of the current;
Converting the voltage command into an optical signal;
Transmitting the optical signal to the drive unit;
With
The drive unit is
During initial setup,
Converting the optical signal into an electrical signal;
Regenerating a carrier signal from the electrical signal;
For each control cycle,
Converting the optical signal into an electrical signal;
Regenerating a voltage command from the electrical signal;
Generating a PWM signal from the voltage command and the carrier signal;
A control method for an electric motor control device comprising:

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